Sunday, February 12, 2012
Valentine's Day is just around the corner. I know you want to make something special for your special someone. I also know that you want to throw a little science geekery into the mix. Here's a few ideas:
Fun with Crystals
Become a silversmith!
Did you know you can grow your own silver? It's easy if you have the right ingredients. All courtesy of a displacement reaction: 2Ag+ + Cu → Cu2+ + 2Ag
What you need:
1 test tube or other glass vessel
0.1M silver nitrate or mercury (be very careful with these!)
Bend the copper wire into a desired shape. Suspend the wire in the 0.1M silver nitrate in the test tube. Place the container in a darkened location where the table will not be bumped or vibrated. The crystals will form quickly, within about an hour, and larger crystals will develop overnight. A warmer place should make the crystals grow faster. If you use mercury, add 5-10 mL of the 0.1M silver nitrate. Have fun and be safe, this kind of chemistry is no joke, but if done right you end up with a very pretty piece!
Growing your own sugar crystals takes some time so you'll want to get started as soon as possible to have a nice sized crystal by the big day. Sugar crystals are very easy to grow. First, tie a string to a pencil or skewer. If you want your crystal to grow into a specific shape then suspend a non-reactive material bent into the shape you want from the string. Set the skewer across the top of a clean glass container such that the bottom of the string/shape does not touch the sides or bottom. In a saucepan, boil 1 cup of water. Then stir in 1 teaspoon of sugar at a time until you have dissolved 3 cups of sugar or until the sugar starts to accumulate at the bottom of the container, not mixing with the water with stirring. You want a saturated solution: Enough sugar so that crystals will form but not too much sugar that new crystals will form on the sugar on the bottom of your container instead of the string. Add your desired shade of food coloring. Carefully pour the sugar solution into your prepared glass container, avoiding getting any undissolved sugar into the container. Set the container in a place where it will not be disturbed, bumped, vibrated, or otherwise moved. If you want, you can gently set a paper towel or coffee filter over the top of the container to avoid dust particles getting into the solution. Check the solution after 1 day to make sure crystals are forming. Let the crystals grow to the desired size, and then remove it from the container and allow it to dry.
If you are having trouble getting your crystal to start or need to speed up the process you may consider attaching a seed crystal to your string. Make a seed crystal by pouring a small amount of your saturated sugar solution onto a plate. Let the water evaporate and then scrape the small crystal from the plate and tie the string around it before suspending it over the glass container.
Write that special person a love letter in invisible ink. There are several ways to make invisible inks that are easy and use everyday ingredients. Some invisible inks work by causing slight damage to the paper so that when the paper is heated it burns the weakened areas, causing the writing to appear. Others work because the chemical itself is invisible but becomes visible when a secondary chemical is applied. Here are a few recipes for invisible ink:
Lemon Juice Invisible Ink:
Apply fresh or bottled lemon juice to a stick, toothpick, cotton swab or thin paintbrush. Write your message on regular white copy paper. Allow the writing to dry. When you are ready for the writing to appear hold the paper up to a lightbulb or other (safe) heat source. Don't like the heat method? No problem. Put salt on the drying writing. After a minute, wipe off the salt and color over the paper with a wax crayon. The message will be revealed.
Cornstarch Invisible Ink:
Make a thin cornstarch solution by mixing together 2 tablespoons cornstarch into 4 teaspoons of water, heating it until smooth. Apply the mixture to a stick or thin paintbrush to write your message, and allow it to dry. When you want to reveal the message simply apply an iodine solution (1 tsp iodine to 10 tsp water).
Baking Soda Invisible Ink:
Mix equal parts of baking soda and water. Apply the mixture to a stick or thin paintbrush and write your message on white copy paper. Allow it to dry. To make the message appear hold the paper up to a lightbulb or other (safe) heat source. Or you can pick the non-heat method and paint over the writing with purple grape juice, a simple acid-base reaction.
Fizzy and Fabulous!
Make homemade fizzy, scented bath bombs. You'll need:
2 tbsp citric acid
2 tbsp cornstarch
1/2 c baking soda
1/4 tsp of a fragrance oil of your choice
3-6 drops food coloring
3 tbsp vegetable oil
In a mixing bowl, combine the citric acid, cornstarch, and baking soda. In a glass measuring cup, mix the fragrance oil, food coloring, and vegetable oil. Slowly incorporate the wet ingredients into the dry, mixing well. Form the mixture into 1 inch balls (or use a 3-D mold for fun shapes!) and place them onto waxed paper. Allow them to dry for 24 to 48 hours before storing them. Store them, or wrap them, in a sealed container away from moisture. To use simply add a few to your bath water and enjoy!
Fresh Fresh Flowers
Keeping Your V-Day Flowers Fresh:
Flowers are plants, and plants need food. Making a floral preservative provides your flowers with both water and food while also containing a disinfectant to prevent bacteria from growing. First, you want to make sure your vase is nice and clean. Next, cut the bottom of the stems at and angle with a sharp knife or scissors to prevent them from sitting flush with the bottom of the vase, and trim off any dead leaves or leaves below the water line (your local florist may have already done this part). Next, mix up a floral preservative with warm water (100-110°F) using one of these recipes.
2 cups lemon-lime carbonated beverage (like Sprite or 7-Up)
1/2 tsp household bleach
2 cups warm water
2 tbsp lemon juice
1 tbsp sugar
1/2 tsp household bleach
1 qt warm water
2 tbsp white vinegar
2 tbsp sugar
1/2 tsp household bleach
1 qt warm water
Remember, have fun with your sciency Valentine's Day projects and be safe!
Sources for these experiments can be found at About.com:
Fizzy Bath Bombs
(image from http://www.etsy.com/listing/65865330/science-valentines)